Thermal insulation batts which are comprised of a layer of low density bulk insulation, such as fiberglass insulation or mineral wool insulation and an asphalt coated paper facing, are well known in the art. The thermal insulation batts typically have tabs located along each longitudinal edge for attaching the batts to the building structural members such as studs or joists. For example, U.S. Pat. No. 1,694,949 issued to Lindsay discloses an early type of thermal insulation batt in which a bulk insulation material is completely enclosed within a moisture-impervious envelope and which further has flange portions for use in securing the batt in position. U.S. Pat. No. 2,263,201 issued to Wheeler et al discloses an insulation batt which is specifically designed for use in building construction and which has a paper facing sheet with integral edge flanges. U.S. Pat. No. 2,913,104 issued to Parker et al discloses thermal insulation batts made of asphalt coated paper or aluminum foil in which the side tabs are formed of a triple layer of the facing material. In the U.S. Pat. No. 4,233,791, issued to Kuhl et al and in U.S. Pat. No. 4,385,477 issued to Walls et al there is disclosed installations which utilize as a vapor barrier sheets made of thermoplastic materials such as polyester shrink films over batts of thermal insulation.
Because untreated paper facings generally do not provide a sufficient vapor barrier, asphalt coatings have been used in combination with the paper facings. The asphalt coating is used to both provide vapor barrier properties to the paper and also to adhere the layer of thermal insulation to the facing. The use of asphalt coated paper facing is not considered desirable because of the manufacturing cost and related problems associated with the required use of molten asphalt baths in the manufacturing process. In addition, the asphalt and the paper both substantially increase the flammability of the thermal insulation batt as well as adding a significant amount of potential fuel to the batt. To reduce the vapor permeability typically encountered with the untreated paper facings, insulation batts have heretofore been prepared using facings made of thermoplastic films. These batts, however, have not been successful because of the relatively low strength of the facings and more particularly because of the unsatisfactory folding characteristics of the tabs formed of the thermoplastic films. The tab portions made from the thermoplastic film tend to tear readily, causing propagation of the tears and a destruction of the vapor barrier of the thermal insulation batt.